BK virus nephropathy in a patient with ABO-incompatible renal transplantation

Abstract:  A 43-year-old woman with end-stage renal disease originating from IgA nephropathy entered chronic haemodialysis therapy. She then received an ABO-incompatible living related renal transplantation. Initial immunosuppression consisted of azathioprine, methylprednisolone and tacrolimus. At 155 days after transplantation, the azathioprine was changed to mycophenolate mofetil for continuous graft dysfunction. Furthermore, a total of three courses of anti-rejection therapy was given. At 665 days after transplantation, diagnosis of BK-virus nephropathy was made by immunohistochemical analysis and viral DNA assay. Therefore the immunosuppression therapy was reduced for graft dysfunction. All five renal biopsy specimens were examined retrospectively in order to determine when the BK virus nephropathy had developed. The expressions of SV40 large T antigens were detected from the third (117 days) to the fifth (665 days) biopsies, with increasing numbers of SV40 large T antigen positive cells. In addition, many cells contained inclusion bodies which were already present in the urinary sediment for 3 months post-transplantation. Although it is difficult to make a diagnosis of early stage of BKVN, we have to consider with caution if urinary cells with inclusion body are seen. Awareness of BKVN at the earliest opportunity is important in order to avoid over-immunosuppression.     

Homozygous Mutation in Synaptic Vesicle Glycoprotein 2A Gene Results in Intractable Epilepsy,Involuntary Movements,Microcephaly, and Developmental and Growth Retardation

BackgroundSynaptic vesicle protein 2A (SV2a) is the binding site of the antiepileptic drug levetiracetam and the only known synaptic vesicle target of an epilepsy medication. To date, no pathogenic mutation in SV2A, which is the gene encoding synaptic vesicle glycoprotein 2A, has been identified in humans. We report a homozygous mutation in the SV2A gene in a patient with intractable epilepsy.MethodsWe investigated a patient with intractable epilepsy, involuntary movements, microcephaly, and developmental and growth retardation. Both parents were multiply consanguineous and an earlier-born brother of the proband had a similar course and died at 7 months of age. Detailed clinical history, imaging, electroencephalograph and metabolic testing were obtained. Full exome sequencing was performed using genomic DNA isolated from the patient and both parents.ResultsExome sequencing identified a homozygous arginine to glutamine mutation in amino acid position 383 (R383Q) in exon 5 of the SV2A gene. Both parents were carriers for the R383Q variant, suggesting that R383Q is a recessive mutation. There were no other candidate alterations in the exome that could explain the phenotype in the proband. The amino acid arginine at position 383 of SV2a gene is evolutionally conserved throughout vertebrates. R383Q change is not observed in known healthy cohorts, exome databases, or the Database of Single Nucleotide Polymorphisms. The R383Q mutation is located in the second adenine binding domain in SV2a protein and may alter adenine nucleotides binding to SV2a.ConclusionOur report provides the elusive evidence that an SV2A mutation can be a cause of epilepsy in humans. Levetiracetam, which binds to SV2A, was not effective as an antiepileptic medication. The location of the mutation in our patient supports an important role of adenine nucleotides binding in SV2A function.     

A novel strategy for targeted killing of tumor cells: Induction of multipolar acentrosomal mitotic spindles with a quinazolinone derivative mdivi‐1

Traditional antimitotic drugs for cancer chemotherapy often have undesired toxicities to healthy tissues, limiting their clinical application. Developing novel agents that specifically target tumor cell mitosis is needed to minimize the toxicity and improve the efficacy of this class of anticancer drugs. We discovered that mdivi‐1 (mitochondrial division inhibitor‐1), which was originally reported as an inhibitor of mitochondrial fission protein Drp1, specifically disrupts M phase cell cycle progression only in human tumor cells, but not in non‐transformed fibroblasts or epithelial cells. The antimitotic effect of mdivi‐1 is Drp1 independent, as mdivi‐1 induces M phase abnormalities in both Drp1 wild‐type and Drp1 knockout SV40‐immortalized/transformed MEF cells. We also identified that the tumor transformation process required for the antimitotic effect of mdivi‐1 is downstream of SV40 large T and small t antigens, but not hTERT‐mediated immortalization. Mdivi‐1 induces multipolar mitotic spindles in tumor cells regardless of their centrosome numbers. Acentrosomal spindle poles, which do not contain the bona‐fide centrosome components γ‐tubulin and centrin‐2, were found to contribute to the spindle multipolarity induced by mdivi‐1. Gene expression profiling revealed that the genes involved in oocyte meiosis and assembly of acentrosomal microtubules are highly expressed in tumor cells. We further identified that tumor cells have enhanced activity in the nucleation and assembly of acentrosomal kinetochore‐attaching microtubules. Mdivi‐1 inhibited the integration of acentrosomal microtubule‐organizing centers into centrosomal asters, resulting in the development of acentrosomal mitotic spindles preferentially in tumor cells. The formation of multipolar acentrosomal spindles leads to gross genome instability and Bax/Bak‐dependent apoptosis. Taken together, our studies indicate that inducing multipolar spindles composing of acentrosomal poles in mitosis could achieve tumor‐specific antimitotic effect, and mdivi‐1 thus represents a novel class of compounds as acentrosomal spindle inducers (ASI).     

Differential targeting and function of alpha2A and alpha2C adrenergic receptor subtypes in cultured sympathetic neurons

Previous research suggested that alpha2A and alpha2C adrenergic receptor (AR) subtypes have overlapping but unique physiological roles in neuronal signaling; however, the basis for these dissimilarities is not completely known. To better understand the observed functional differences between these autoreceptors, we investigated targeting and signaling of endogenously expressed alpha2A and alpha2CARs in cultured sympathetic ganglion neurons (SGN). At Days 1 and 4, alpha2A and alpha2CARs could be readily detected in SGN from wild-type mice. By Day 8, alpha2A ARs were targeted to cell body, as well as axonal and dendritic sites, whereas alpha2C ARs were primarily localized to an intracellular vesicular pool within the cell body and proximal dendritic projections. Expression of synaptic vesicle marker protein SV2 did not differ at Day 8 nor co-localize with either subtype. By Day 16, however, alpha2C ARs had relocated to somatodendritic and axonal sites and, unlike alpha2A ARs, co-localized with SV2 at synaptic contact sites. Consistent with a functional role for alpha2 ARs, we also observed that dexmedetomidine stimulation of cultured SGN more efficiently inhibited depolarization-induced calcium entry into older, compared to younger, cultures. These results provide direct evidence of distinct developmental patterns of endogenous alpha2A and alpha2C AR targeting and function in a native cell system and that maturation of SGN in culture leads to alterations in neuronal properties required for proper targeting. More importantly, the co-localization at Day 16 of alpha2C ARs at sites of synaptic contact may partially explain the differential modulation of neurotransmitter release and responsiveness to action potential frequency observed between alpha2A and alpha2C ARs in SGN.     

Is there an association between SV40 contaminated polio vaccine and lymphoproliferative disorders? An age–period–cohort analysis on Norwegian data from 1953 to 1997

Between 1955 and 1963, an estimated number of 150 million people in various parts of the world, including Norway, received poliomyelitis vaccine possibly contaminated with infectious simian virus 40 (SV40). Human studies have investigated the hypothesised association between SV40 and various cancers, but the results have so far been contradicting. The aim of the present study was to examine Norwegian cancer incidence data to assess a possible association between birth cohorts assumed to have been subjected to the vaccine and the incidence rate of lymphoproliferative disorders (excluding Hodgkin's lymphoma), further subdivided into non-Hodgkin's lymphoma (NHL), lymphocytic leukemia and plasma cell neoplasms. Between 1953 and 1997, the incidence rate of lymphoproliferative diseases combined increased about 3-fold in both males and females. Subgroup analysis showed that this increase was largely attributable to NHL. Age-period-cohort modelling of the subgroups, as well as of all groups combined, showed that the cohort effect was more prominent than the period effect. However, the variations in incidence patterns across the birth cohorts did not fit with the trends that would be expected if a SV40 contaminated vaccine did play a causative role. Thus, our data do not support the hypothesis of an association between the vaccine and any subgroup of lymphoproliferative diseases.     

Biologic, cytogenetic, and molecular factors in mesothelial proliferations

Although mesothelioma cases may have peaked in the 1990s in developed countries, it is expected that there will be over 70,000 cases diagnosed in the United States over the next 5 decades. With the industrial expansion in Southeast Asia and China and the continued use of asbestos, an epidemic of mesothelioma cases is anticipated over the next several decades. A considerable amount has been learned about the cytogenetic and molecular genetics of mesotheliomas. However, in-depth studies are needed to further define specific factors that may provide for early diagnosis, surgical treatment, oncologic management, and gene therapy. Serologic markers for surveillance of those with asbestos exposure and at risk for mesothelioma are needed. Targeted therapy using molecular markers and gene therapy may provide a means to reverse mesothelial proliferations or stabilize tumor growth and allow for surgical resection. The future holds great promise in identifying mesothelioma gene expression profiles (genomics, gene microarrays) and proteins (proteomics) that may produce the key to dealing with this dismal and devastating neoplasm.     

Immunohistochemical localisation of the voltage gated potassium ion channel subunit Kv3.3 in the rat medulla oblongata and thoracic spinal cord

Voltage gated K+ channels (Kv) are a diverse group of channels important in determining neuronal excitability. The Kv superfamily is divided into 12 subfamilies (Kv1-12) and members of the Kv3 subfamily are highly abundant in the CNS, with each Kv3 gene (Kv3.1-Kv3.4) exhibiting a unique expression pattern. Since the localisation of Kv subunits is important in defining the roles they play in neuronal function, we have used immunohistochemistry to determine the distribution of the Kv3.3 subunit in the medulla oblongata and spinal cord of rats. Kv3.3 subunit immunoreactivity (Kv3.3-IR) was widespread but present only in specific cell populations where it could be detected in somata, dendrites and synaptic terminals. Labelled neurones were observed in the spinal cord in laminae IV and V, in the region of the central canal and in the ventral horn. In the medulla oblongata, labelled cell bodies were numerous in the spinal trigeminal, cuneate and gracilis nuclei whilst rarer in the lateral reticular nucleus, hypoglossal nucleus and raphe nucleus. Regions containing autonomic efferent neurones were predominantly devoid of labelling with only occasional labelled neurones being observed. Dual immunohistochemistry revealed that some Kv3.3-IR neurones in the ventral medullary reticular nucleus, spinal trigeminal nucleus, dorsal horn, ventral horn and central canal region were also immunoreactive for the Kv3.1b subunit. The presence of Kv3.3 subunits in terminals was confirmed by co-localisation of Kv3.3-IR with the synaptic vesicle protein SV2, the vesicular glutamate transporter VGluT2 and the glycine transporter GlyT2. Co-localisation of Kv3.3-IR was not observed with VGluT1, tyrosine hydroxylase, serotonin or choline acetyl transferase. Electron microscopy confirmed the presence of Kv3.3-IR in terminals and somatic membranes in ventral horn neurones, but not motoneurones. This study provides evidence supporting a role for Kv3.3 subunits in regulating neuronal excitability and in the modulation of excitatory and inhibitory synaptic transmission in the medulla oblongata and spinal cord.